Evidence for binding of at least two factors, including T-rich strand-binding factor(s) to the single-stranded ARS1 sequence in Saccharomyces cerevisiae.

To study the mechanism of initiation of eukaryotic chromosomal replication, we examined protein factors interacting with the ARS1 region located near the centromere of chromosome IV in Saccharomyces cerevisiae. Using the gel shift assay, we found protein factor(s) which specifically bound to the T-rich strand of the region containing the core consensus and its flanking sequences in ARS1, but not to the opposite strand. We designated this factor ATS (ARS1, T-rich strand-binding factor(s]. Similar specific complexes were also detected with oligonucleotide probes specific for the H4 or C2G1 ARS. As we have previously identified another binding factor, we conclude that at least two factors bind to the single-stranded ARS1 sequence.